| 摘要 |
A discharge tube for emitting light of the present invention includes an inner bulb (4) including a hollow portion (42) for defining therein an arc discharge chamber which encloses therein gas for emitting light, the inner bulb further including a pair of electrodes (41a,41b) and a pair of metal members (43Ba,43Bb) each of which is connected to a corresponding one of the pair of electrodes (41a,41b) , the pair of electrodes being projected in the arc discharge chamber (42') from the inner bulb (4) and the pair of metal members (43Ba,43Bb) being projected outwardly of the inner bulb (4) the hollow portion (42) having an outer diameter of a first value and an outer tube (5) for sealingly enclosing therein the inner bulb (4), the outer tube (5) including a small-diameter portion having an outer diameter of a second value which is equal to or smaller than the first value, wherein the inner bulb (4) is held in the interior of said outer tube (5), with a gap being formed between an outer surface of the inner bulb (4) and an inner surface of said outer tube (5), in such a manner that the outer tube (5) supports the metal members (43Ba,43Bb) projected outwardly of the inner bulb (4). <IMAGE>
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